Engineering

Q1.

In a basic transmission line, the voltage at the receiving end without load is 660 V; and it is 420 V with full load. What is the percentage of voltage regulation ?

1)

47%

2)

57%

3)

67%

4)

77%

5)

None of these

Answer : 57% Explanation :

Voltage regulation =(VNL - VFL) / VFL

= (600 - 420)/420 = 0.57 or 57%

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Q2.

A disk unit has 24 recording surfaces. It has a total of 14000 cylinders. There is an average of 400 sectors per track. Each sector contains 512 bytes of data. What is the data transfer rate at a rotational speed of 7200 r.p.m.?

1)

68.80 ×10^6 bytes/s

2)

24.58 ×10^6 bytes/s

3)

68.80 ×10^3 bytes/s

4)

24.58 ×10^3 bytes/s

5)

None of these

Answer : 24.58 ×10^6 bytes/s Explanation :

The data transfer rate = (No. of sector/track)×(Bytes in each sector)×(Rotational speed (revolution per sec.))

Rotational Speed = 7200 rpm × (1/60) = 120 rev. per sec.

= 400×512×120 = 24.58×106

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Q3.

Consider the following processes which arrived in the order P1, P2 and P3:

Process Burst Time

P1 24 ms

P2 3 ms

P3 3 ms

What is the average waiting time by FCFS scheduling ?

1)

17 ms

2)

19 ms

3)

21 ms

4)

23 ms

5)

None of these

Answer : 17 ms

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Q4.

Consider the following statements regarding the functions of an operating system in a computer:

1. It controls hardware access

2. It manages files and folders

3. It provides a user interface

4. It manages applications

Which of the above statements are correct ?

1)

1, 2 and 3 only

2)

1, 2 and 4 only

3)

3 and 4 only (d)

4)

1, 2, 3 and 4

5)

None of these

Answer : 1, 2, 3 and 4

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Q5.

The noise factor of an attenuator pad that has an insertion loss of 6 dB is -

1)

0.25

2)

0.5

3)

2

4)

4

5)

None of these

Answer : 4 Explanation :

Insertion loss= 6dB

Insertion loss (IL) is given by

I.L. = 10 log (PT/PR), where PT is the transmitted power PR is the power received by the load after insertion 10 log (PT/PR) = 6 dB

So, (PT/PR) = 100.6 = 4

Noise factor = (PT/PR) = 4

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Q6.

A weighted complete graph with n vertices has weights 2|i – j| at edges (vj, vj). The weight of a minimum spanning tree is -

1)

n2/2

2)

n/2

3)

2n – 2

4)

n – 1

5)

None of these

Answer : 2n – 2

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Q7.

An asynchronous link between two computers uses the start-stop scheme, with one start bit and one stop bit, and a transmission rate of 48.8 kbits/s. What is the effective transmission rate as seen by the two computers ?